This specification relates to cookies that can be used to identify a client or user in Internet interactions.
Generally, the term “cookie” is used to refer to HTTP (Hypertext Transport Protocol) or web cookies. However, the term will be used in this specification in a broader sense to include any collection of information, whether stored in a file or otherwise, provided by a web site to be stored on a client device. Generally, a cookie includes information about an individual's or the client's use of a web site. Thus, the term includes not only conventional web cookies but also other technologies, e.g., “Local Shared Objects,” which are also known as “Flash cookies.”
When an advertisement is downloaded from an ad server by a user's browser, a cookie, associated with the ad server, is provided by the ad server to the browser. The cookie can be used to track how many unique browsers have downloaded the advertisement and how many times the advertisement has been downloaded by any one user's browser. An advertiser can incorporate content from the ad server into a conversion page. When the user visits the advertiser's conversion page, the information in the cookie is provided to the ad server when the content is downloaded by the user's browser.
Ad servers often serve multiple advertisements for a variety of advertisers. Conventionally, a single cookie associated with the ad server is used to track and identify a user with respect to all advertisements served by the ad server. Instead of using cookies, some ad servers record and track a user based on the user's IP (internet protocol) address and browser agent identity.